Spark plug



Jan. 15 11324.

F. H. ELWELL SPARK PLUG Filed March 29, 1920 Patented Jan. 15, 1924.

FRANKLIN `H. ELWELL, OF CHICAGO, ILLINOIS.

SPARK PLUG.

Application filed March 29, 1920.

7 10 all whom t may concern.'

Be it known that I, FRANKLIN HxELWELL, a citizen of the United States, residing at Chicago, in the county of'Cook and State of Illinois, have invented' certainnew andl useful Improvements in Spark Plugs, of which the following is a description.

My invention belongs to that general class of devices known asspark plugs. The invention has among its objects the production of a device of the kind described that is simple, convenient, durable, reliable, efficient and'satisfactory for use wherever found applicable. It'has particularly as an object the production of a spark plug of the kind described which may be easily cleaned or theparts-renewed Without'in any Way disturbing thegastight joints which maybe made permanent. The invention" has among its objects the production'of a plug of a kind described ythatvvill not easily `become fouled and short-'circuited, and Whichvvill stand a greatamount of heat Without danger of breaking or becoming yinoperative or inetlicient. Many other objects and advantages of the construction herein shown and describedwill' be obvious to those skilled in the art from-the 'disclosureiherein given.

To this end'myiinvention consistsin the novel construction, 'arrangementand combination of partsherein shown and'described and more particularly pointed out in the claims.

In the drawings, wherein like reference characters indicate like or corresponding parts,

Figure l is a sectional view through one form of vmy device;

Figure 2-is a similar view` of a slightly modified construction ofL the electrode sleeve;

Figure 3 is a sectional view illustrating another` modified formv of sleeve;

Figure i--is a sectional. View similarl to Figure lV ilhistrating another construction similar to the preceding; and

Figure 5 is anend elevation of the plug shown in Figure 1.

Referring tothe drawings, 1 represents a body partici suitable size, shape and material which is provided with an extending portion threaded asiat 2 for insertion into andy engagement at the spark plug opening on the engine, the same being-preferably formed as at 3 so that it may bev engaged by a suitable wrench and turned down into place. The body vpart is'preferably tubu- Serial N o. 369328.

lar, as shown,.the same being formed with the opening enlarged at the outer end as indicated at 4t so as to provide a shoulder Arranged inthe recess at the outer end is a core or part V(i of suitable n'iateriahvpreferably insulating material such as porcelain or ythe equivalent. An asbestos co per gasket 8, orthe equivalent, is arrangel at the inner end ofthe porcelain and a gasket or copper, or equivalent, ringl() is arranged at the shoulder 7, the body end being turned over asindicated at 9 so that the porcelain or the like-is securely and substantially per! manently ylocked in place, and a vgastight joint secured between the porcelain and body. Arranged in t-he porcelain is anelecw trode, the inner portion 12y of which is preferably formed so-as to kbe permanently retained in the porcelain, for example, cast therein,-while the outer end 11' constitutes. a binding part. Theinner endof portion .1'2 is recessed and internally threaded. ADetachably carried bythe electrode 12 is an electrode '15, the same extending "from'the porcelain body` to the inner end ,of the body 1. The inner end of thexporcelain core 6 is preferably recessed, Aas shown, and in the preferred construction is shouldered `as at 6. As will be noted, the-inner end of the electrode 15 is threaded as at l16. The outer end is provided lwith ahead 17 which is shown Vwith an .opening or hole 20 through the saine. At the head enti is provided a plate I18 or its equivalent arrangedto cooperate `with the electrode or contact members 19 carried'by the body. The elect-rode'i is sho-wn provided withan insulating covering consisting of the sleeve parts 21, 22 being diskseftendingito adjacent the walls of thebore ot' thebody. A disk 22 is also provided bythe'head and adjacent sleeve 2l at the open or inner end ot the plug. The sleeve parts 21 may be made of mica, cr the equivalent, the disks 22 being also preferably of mica of' the desired thickness and size.

The construction shown'in Figure 2 is similar, representing the detachable electrode which is threaded as at 26fto engage the cooperatingelectrode part inthe porcelain core orbo'dy. The electrode isprovided with the head 27 and plate 28 similar to thatdescribed. In thiscase, however, the sleeve 30,instead of beingsectional, is-in one piece, only one disk 29 being employed. Another modified sleeve construction is shown in Figure 3 in which 3l represents a sleeve, in this case preferably of porcelain or like material, provided, however, with ends 32 and 33 of mica or like material which may be compressed or will yield upon expansion of the sleeve.

Referring to the construction illustrated in Figure 4, 36 represents the body of metal or the like having` the projecting or inner end threaded at 3T for engagement with the plug opening in the engine. ylhe body 36 carries a core 38 of porcelain or the equivalent, 39 and 40 being rings of asbestos or copper for sealing and preventing leakage between the porcelain and the body. ln the core 38 is an electrode 4l. provided with an enlarged end 42 internally threaded and with the exterior end 43 projecting to the exterior of the porcelain for a binding post. Electrode 4l is preferably embedded in the porcelain body 88. A cooperating electrode member 44 is provided, the same being arranged to engage a threaded recess in the head 42 of the electrode 4l. lt will be noted that the body of the porcelain 38 is recessed as at 4G, the same extending, however, as at 45 so as to form a shoulder and a transversely extending portion between the recess and the end of the electrode head 42. Arranged on the electrode 44 is a sleeve 47 of porcelain or the like, 4S and 50 being bushings or packing members of mica or like material which may be arranged at the inner end of the sleeve and between the sleeve and head 49 of the electrode. ln this case the sleeve is shown with a projecting rim or flange 5l. The head 49., as shown, carries a plate 52 and the body 36 carries one or more pins 53 at the inner end of the body part.

With the construction shown in Figure l, the device is applied to the engine, and electrically connected in the usual manner. The current passes through electrodes l2 and l5 and plate 18, and jumps across to the mem bers 19 and flows into the body and thence to the ground. While the mica disks 22 may have a tendency to vibrate, thus preventing the accumulation of carbon, they become incandescent and burn off the ca:- bon preventing the accumulation thereof, and preventing the samefrom short-circuiting the plug and reducing its efficiency. 'lo clean the plug it is only necessary to detach the electrode 15 and this may be done by inserting a tool at the hole 20, turning the same, or by using pliers or a wrench or any equivalent for the purpose. The operation of the plug shown in Figure 2, or the plug with a sleeve shown in Figure 3, is substantially similar. lt will be noted that the core 6 is not removed in cleaning the plug and being permanently set or fixed in the body part, the same havingbeen made gastight remains gastight.

will be noted that with the construction shown in `Figure 4, while a gastight and non-leaking joint is formed by the disk and disk 50, that, should there not be a tight fit at the disks, gas would have to travel downwardly, and thence inwardly toward the electrode 44, and thence downwardly, and thence outwardly and downwardly, and thence inwardly, and thence outwardly along electrode 4l. The electrode 4l, is, however, permanently formed in the body 38, consequently there is small chance for leakage for the gasmust travel the tortuous path described, and a portion would substantially always be tight. Owing to the yielding of the non-combustible packing 48 and 50, expansion of the sleeve 47 is p ssible without fracturing the sleeve. `With this construction the thin rim 5l becomes incandescent and tends to burn ofi' any carbon and oil accumulatingabout the open end of the plug. The same may be easily cleaned by removing the electrode and sleeve should the same be desired or found necessary at any time. The detachable electrode and type of sleeves shown in Figures l to 3 may be substituted for that shown in Figure 4, if desired.

Having thus described my invention, it is obvious that various immaterial modifications may be made in the same without departing from the spirit of my invention, hence l do not wish to be understood as limiting myself to the exact form, construction, arrangement and combination of parts herein shown and described or uses mentioned.

W hat l claim as new and desire to secure by Letters Patent is:

l. ln a spark plug of the kind described and in combination, a n'letallic body part having an opening therethrough, a core of insulating material arranged in said body part and projecting therefrom at the outer end thereof, gaskets arranged between the body and core, means for substantially permanently and inseparably securing said. core in place,l an electrode comprising two parts detachably connected together, one part permanently imbedded in said core between its ends so as to be integral therewith and projecting therefrom at the outer end thereof, the inner end of said electrode part enlarged and provided with a threaded recess, said core recessed at it inner end and having an opening connecting with said recess and with the recess in said electrode. rlhe other electrode part being of a size to closely lit within said opening and threaded so as to engage with said recess of the first mentioned electrode part, Said second electrode provided with a head at its opposite end and flanged about said head, a sleeve of insulating material arranged between the head of the second electrode and engaging the bottom of the recess in said core, and provided with a very thin flange of insulating material extending outwardly to adjacent the inner wall of the opening in the body part.

2. In a spark plug of the kind described and in combination, a metallic body part having an opening therethrough, a core of insulating material arranged in said body part and projecting therefrom at the outer end thereof, gaskets arranged between the core and body, an electrode carried by said core and projecting therefrom at the outer end thereof, the inner end of said electrode constructed to engage a cooperating part, said core recessed at its inner end and having an opening therethrough registering with the recess in said electrode, a cooperating electrode part of a size to extend through said registering openings and constructed to engage with the first mentioned electrode,

said second elect-rode provided with a flanged head at its opposite end, a sleeve of insulating material in the bottom of the recess of said core and engaging the head of said second electrode, and yieldable gaskets of flexible insulating material arranged at the end of said sleeve between the sleeve and core and the head of said second electrode.

In testimony whereof, I have hereunto signed my name in the presence of two subscribing witnesses.

FRANKLIN H. ELWELL. Witnesses ROY W. HILL, BERTHA HARTMANN. 

